Over the past 20 years, the developing kidney has received recognition as a powerful model system to investigate the molecular regulation of several developmental programs including mesenchymal-to-epithelial conversions, branching morphogenesis, and segmentation of tubular structures into functional domains. This is due, in large part, to the generous support of the NIH in funding fundamental scientific research. This research justified the use of several model organisms to study kidney development and generated the large number of mutant mouse lines with kidney defects that are now available for analysis. Most importantly it has provided novel insight into the development of kidney structure. It is now timely to address the development of renal function. Although there is a rich literature on adult renal function, it is a complex subject and may be intimidating to young investigators lacking a strong physiology background. I propose that the NIDDK organize a course on renal physiology for these investigators and encourage them to expand their thoughts and studies towards the acquisition of renal function during embryogenesis. This paradigm shift towards physiology would bring adult kidney disease into the field of developmental biology. It is likely to be more effective, in the long run, than targeting research towards a specific diseased state, which may or may not be due to primary defects in kidney function.